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Archived threads in /sci/ - Science & Math - 89. page
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File: watren.jpg (57 KB, 800x514) Image search: [iqdb] [SauceNao] [Google]
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Is water retention a real thing or is it a fad to make fat people feel better?

>INB4 "Go to /fit"
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>>8455711
Search "edema"
>>
>>8455711
of all things available, why such a disgusting picture
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>>8455716
/tv/ is a minority on this site

They used to be fairly dense with information, well explained, and coherent. Now they seem to be filled with irrealavant and distracting fluff that isn't of no use to the student.

I had my cousin over for a visit today, and he had me help him with some of his trig homework. The textbook they were having him read was complete and utter garbage compared to the textbook I had that was published in 84.

Why do they give students today's such shitty textbooks? Why the hell are they still even publishing new editions of books covering basic concepts like trigonometry...
>>
>>8455707
HEY GUYS, LET'S BUILD A CAPITALIST ECONOMIC SYSTEM IN WHICH THE MEANS OF PRODUCTION OF TEXTBOOKS ARE IN THE HANDS OF LARGE COMPANIES AND MILLIONS UPON MILLIONS OF STUDENTS ARE IN NEED OF TEXTBOOKS EACH YEAR!

GEE, I WONDER WHAT COULD POSSIBLY GO WRONG!
>>
>>8455717
The issue isn't capitalism. The issue is the fact school is publicly funded and the free market has zero say in determining matters( such as what textbook to use) as there are no penalties in getting it wrong.
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>>8455747
BINGO!

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>The Sun has fallen out of orbit and is going to crash into the Earth. Humanity has randomly chosen people to enter an underground nuclear shelter with enough food and provisions for the next 50 years until the Earth is habitable again, luckily you were picked.
>You are allowed to bring one scientific instrument with you.

Choose wisely /sci/...
>>
>the sun has fallen out of orbit

A fucking dildo
I want to ram something up my ass one last time before the solar system fucking collapses in the next few minutes
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>>8455619
>The Sun has fallen out of orbit and is going to crash into the Earth

I wonder how big the crater in the earth would be if that happened. :^)
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>>8455619
What if the sun gets deflected by the moon?

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Guys im going to be the next alber einstein ask me anything
>>inb4 you are not smart and i am the real smart guy here
>>
>>8455618
How can we formulate QM without reference to imaginary numbers?
>>
so OP how do you wanna become the next einstein if you cant even spell his name correctly
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>>8455631
Ok, good question!
Say we have 1 thousand dogs, if W=Fdx and I = Fdt then W/I = |v|

Also /SSG/-Sequences and Series General
>>
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integral diverges, series diverges
it doesn't even tend to zero baka
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>>8455612
The argument is not monotonicly decreasing you mong.

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You folks hyped for ITER or what? This will blow every single solar or other "clean" energy arguments completely out. Hell, you could probably find enough deuterium on Mars to run this thing.
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It's still like 15 years away from full operation. And that's assuming no more setbacks. It has already been pushed back a lot from original estimates.

Assuming it works, it's still only a proof of concept--- that concept being a fusion reactor that puts out more energy than is put in. It would be up to its successors to "blow every other clean energy argument out". It would still be awesome.
>>
>>8455560
this

ITER's goal is to be a test bed for Fusion and "energy out" Fusion. Not as an actual proto-type for a producible fusion reactor.
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>>8455519
Fusion research is great, but I can't see this (or anything similar) as ever being viable as a practical energy source.

Fast neutrons make it much harder to get useful energy out, as well as making radiation shielding a nightmare. Capital cost will be astronomical (capital servicing is the primary operating cost for fission).

What problem does this solve that fission isn't a better solution for?

IMO, fusion power is only going to be viable if we can get aneutronic fusion working, and...

Can someone explain (or prove, though not required) why two intersecting perpendicular lines diagonally across a plane with an infinitely small circle of radius r in the center does not disprove the Four Color Theorem? In the middle do they all not touch and either two sections of the four quadrants would be forced to touch along the sides, or through the center, or standing as it is in pic related where the four quadrants support the Four color theorem, the circle that is colored any color would touch one of the four quadrants?
>>
Can you articulate in a little shorter sentences?

Also, state what you think the theorem is about.

Also
>infinitely small circle of radius r
while you shouldn't even fall for the Descartes meme of thinking it needs points to make up for lines and planes, please don't reason with infinitesimals like properties for finite things apply to them
>>
In mathematics, the four color theorem, or the four color map theorem, states that, given any separation of a plane into contiguous regions, producing a figure called a map, no more than four colors are required to color the regions of the map so that no two adjacent regions have the same color. Two regions are called adjacent if they share a common boundary that is not a corner, where corners are the points shared by three or more regions.[1]

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Is medicine a meme?
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>>8455453
Yes. Yes it is.
Galen is the Lord of meme-lords.
>>
Yes Tbh I rely on the glory of the Lord to heal me instead
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>>8455453
Sage

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What's the /sci/ view on GMO's?
>>
The factual one. It's fine. We've genetically engineered food for thousands of years already.

Patents and shit is a separate issue however.
>>
It's like any other food, just better.
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>>8455444
By GMO OP obviously means taking genes and segments of DNA from one species and putting them into another species. What we have been doing for thousands of years is artificially breeding plants and animals for select traits we desire instead of leaving them subject to natural selection.

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>lab has 9-2÷1/4+1 beakers
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>>8455364
2 beakers?
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>>8455364
how do you have half a beaker?
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>>8455364
Why would you use both ÷ and /? It's retarded

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how do i stop fucking up my exams
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>>8455322
increase you're IQ
>>
study
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>>8455322
Studying and if that doesn't work, give up and learn to live with not-so-good grades (ps. You don't need high grades to becomea scientist)

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Are MD-PhD programs a meme?
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>>8455282
>is x a meme
>thinly veiled frogpost

Shitposting retard.
Saged and hidden.
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>>8455282
Longest and most expensive pathway to a paycheck in human history probably, but at the end of the day probably a better career than normie medicine.
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>>8455308
>too autistic for board culture
>too much of a brainlet to answer
>breaking global rule 7 with le sage le downboat

Funny you say that when you just crawled out of your reddit safe space.

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What's does /sci/ thinks of spirit cooking and the latest wiki leaks shit saying Hillary is involved in satanic rituals? Come on it can't be true r-right? I'm that kind of guy that if I saw this I would just say go back to >>>/x/ and every part of my brain is screaming that that's a false flag that's there's no supernatural phenomena and that I'm a faggot for thinking that shit is possible. But I'm kinda scared this shouldn't be happening to me. I'm a physicist for gods sake.
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>>8455249
don't you have a /pol/ thread to be roleplaying in
>>
Orgy island sounds very plausible, occult stuff sounds like people decorating the truth a little bit.
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>>8455292
Yeah that must be it. Still scared of this shit. Fuck I'm solving some integrals before going to sleep.
Godspeed everyone.

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One famous one is about the claim that a set which has more elements then the natural numbers but less then the real numbers.
It has been proven that it is impossible to construct such a set but it is also impossible to proove that such a set does not exist.

To elaborate further:

If you are not familiar with the idea of sets they basically represent a "bucket" which contains "things" called elements.

If these "Buckets" have finite elements there are two ways to compare how many elements.
You could could count the elements...
>>
Can somebody explain Godel to a pleb like me?

I'm a physicist, not a mathematician.
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>>8455213
tl;dr some math statements (theorems) involving numbers cannot be proven or disproven under certain axiomatic systems.
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>>8455352
But people say

>"There are true statements that cannot be proven"

How can it be that a statement is true and not provable?

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hi guys this is the first time I come here so I'm sorry if it's against the rules or something, but could you confirm me if the answers are correct for each question?

this is an exam from last year and I wanted to see if my answers are correct since I don't trust whoever did it first.
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>>8455154
No source voltage?
What is V_f or V_t or V_+ or whatever that means
V_R2 = V_Z obviously
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>>8455178
Vf = source voltage

why is Vz = VR2? the zener is inteverted
>>
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Of course it is inverted, that's the principle. It's in parallel to R2.

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Caltech researchers have found evidence suggesting there may be a "Planet X" deep in the solar system. This hypothetical Neptune-sized planet orbits our sun in a highly elongated orbit far beyond Pluto. The object, which the researchers have nicknamed "Planet Nine," could have a mass about 10 times that of Earth and orbit about 20 times farther from the sun on average than Neptune. It may take between 10,000 and 20,000 Earth years to make one full orbit around the sun.

"The possibility of a new planet is certainly an exciting one for me as a...
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>>8455105
Plow twist
Its a black hole and it's going to kill us :^)
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>>8455105
If planet X exist, would it be more likely that it would be something from outside our solar system captured by our sun or a planet that got shot way out there
>>
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Nibiru is coming

what did I do
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>>8455038
$\exp\left(\frac{1}{x}\right) = \exp (x^{-1}) \neq \exp( - x )$
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>>8455047
lol, thanks. I'm a dingus. Guess I'll be deleting this so as to not pollute up the board.
>>
>>8455047
>>8455038
what is this, are you doing this in university op ?
i was doing this shit in 10th grade. please tell there's more to uni that this, or i'll go straight into pure math, even if i fail it

File: tronblackgal.jpg (781 KB, 1536x776) Image search: [iqdb] [SauceNao] [Google]
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Serious question:

How could you use virtual reality to solve mathematical problems?
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>>8455010
Simulate synesthesia
>>
what mathematical problems....
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>>8455015
Any. E.g. number theory problems.

>>8455014
Seing colors? Do you have a concrete idea how that helps solving something?

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what happens to an object when it enters a black hole
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If it hasn't spaghettified it will keep falling and eventually spaghettify.
>>
It stumbles into an alternate dimension where everything is super fucking gay
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>>8454964

does this crap blow anyone else's mind? imo bayesian neural networks are the coolest thing since sliced bread.

>Having recovered the latent manifold and assigned it a coordinate system, it becomes trivial to walk from one point to another along the manifold, creatively generating realistic digits all the while

http://blog.fastforwardlabs.com/post/149329060653/under-the-hood-of-the-variational-autoencoder-in
>>
no, but im mentally handicapped so i dont rly understand it tbqh
>>
What is this?
>>
>>8455247
it's the process of using neural networks to uncover the latent manifold on which some collection of data lies, once you have said manifold you can do things like hop around on it and sample fake data that closely resembles real data.

for example, here are some generated images of bedrooms from a bedroom manifold.

and here's a paper that improves superresolution techniques by projecting an enhanced image onto a manifold of natural images
https://arxiv.org/abs/1609.04802

File: dump.jpg (2 MB, 2382x2078) Image search: [iqdb] [SauceNao] [Google]
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You know, looking at this picture you can't help but think that in at least 1 galaxy there's some alien civilization, probably advanced enough to go around planets and starts (via cryostasis or whatever) and establish colonies.
Humanity one day might do the same, it's fine. Thing is, we're never going to meet aliens, it's just too unlikely. Crossing galaxies is going to take a fuckton of years and even then, when you arrive, the galaxies are absolutely fucking huge. And the inverse square law is such a bitch and makes radiowaves decay so quickly its...
>>
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>>8454901
It's not a bad thing to not meet aliens. I personally prefer a scnenario like Asimov's Foundation where the galaxy is exclusively inhabited by humans, so much easy.

Aliens are not safe. We could be ants compared to their intellect.

I agree with you about intergalaxy travel, too complex.
>>
If we make something that can go fast enough for trips throughout the galaxy to be reasonable, sending probes to other galaxies will probably follow within decades.
>>
i disagree. if the universe is never ending and that means that somewhere out there in time is smart enough to travel at the speed of light at all times.

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>The man who knew infinity
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>>8454892
>dies probably earlier than any other scientist
>mfw his formulaes still solve problems on black holes and cosmology
gg
>>
*came relatively near to without reaching infinity
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>>8455096
fml

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Copper (II) cyanurate
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>>8454878
Recrystallized paracetamol from acetone
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>>8454883
Sulfur recrystallized from toleuene
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>>8454885
Some KMnO4

How unhealthy is smoking really?
>>
Killed more people in the last century than all the wars combined.
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>>8454858
After researching it I've come to the conclusion that it's not unhealthy at all, certain groups that try to push a biased scientific view of smoking basically cherry pick the shit out of their studies and data, while completely downplaying the role that certain transmittable diseases have in causing so called smoking-related illnesses. It's called confounding by infectious disease.

http://sphweb.bumc.bu.edu/otlt/MPH-Modules/BS/BS704-EP713_Confounding-EM/BS704-EP713_Confounding-EM4.html

Of course groups like the FDA and WHO don't ever want to consider this so they can claim shit like smoking or meat causes cancer.
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>>8454974
\$1 has been deposited into your account.

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What is it being a graduate student? One of TAs who is a grad student says that now that she's experienced being one, she would never recommend it to anyone who might be considering it. She also always seems pretty lifeless and gloomy, but I don't know if that's her as a person.

pic unrelated
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>>8454800
What is it like being a grad student***
>>
Yea, it sucked. I didn't for 8 days on a streak and my sleep quota was 5hrs/night.
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>>8454874
>didn't take a shower

File: 1477594313788.gif (407 KB, 359x371) Image search: [iqdb] [SauceNao] [Google]
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>Watching grad student present his thesis topic.
>Using FEM to model something.
>Decides he should explain FEM to the room.
>Draws xy axes and a curve.
>Draws rectangles under the curve.
>Says we approach the real solution as the width of each rectangle approaches 0 or as the number of rectangles approaches infinity.

Was he memeing? Because that seemed a lot like a Riemann sum.
>>
>>8454794
lol, sounds like Riemann sums/Integration indeed;
guess he wanted to sound superior than all us Calculus dolts...
Or maybe he's incompetent.
*shrug*
>>
Was it his whole thesis or just something he used in passing ? I mean Riemann sums *are* used to compute integrals, I dunno why kids here are so shocked to hear that grad students use elementary tools (especially in non-math fields).
>>
>>8454844
You should not have to present something as basic as integration to a thesis defense committee and the rest of the audience at the graduate level. Maybe in a freshman course but not graduate. If someone doesn't know how integration works tell them to ask a freshman calc student to explain it to them

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>>uni student doing undergrad research on concrete

It's actually quite impressive all the admixtures and reinforcements available on the market

The big problem is, either you have concrete that is rated 14ksi and performs absolutely horrible under elevated temperatures, or concrete that can endure 700°C but loses 80% of its compressive strength post heat.

Also; has anyone heard of concrete that's repairs itself being exposed to water?
>>
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>>8454788
That is some cool shit, where are you going to uni? I interned in rock mechanics this summer, so I ran a lot of compressive strength tests with rock cores. Worked pretty closely with a concrete engineer though.
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>>8454788
not a real thing
>>
>>8454807
New York city college of technology

File: example.gif (26 KB, 400x400) Image search: [iqdb] [SauceNao] [Google]
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So i was checking out Cauchy's rigidity theorem, which basically says that any convex polyhedron is rigid. This statement is however not true for a non-convex polyhedron. There may be some continuous deformation that leaves sides and faces intact, but changes angles between faces. A well known example of this by Klaus Steffen can be found in the image.

Now Idjad Sabitov proved further that, although such a continuous deformation changes angles between faces, it does conserve the volume enclosed by those faces.

Here's where i get confused, because this...
>>
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>>8454741
folding cube in question
>>
Read up on everything you mentioned and came to the same conclusion you did. I agree that this volume is clearly changing while the faces remain rigid. Do you have the original Connelly article / Bellows conjecture? Maybe we don't understand something about the class of non-convex polyhedra they're using.
>>
>>8454782
I found the original proof:
https://www.math.ucdavis.edu/~deloera/MISC/BIBLIOTECA/trunk/Connelly/Connelly3.pdf
In it they speak of a "flex" of a surface (triangulated).
For the definition of a "flex" i find the following article which defines it for graphs representing polyhedra
with Connelly as co-writer, leading me to think this must be the proper definition.

However, this doesn't help at all. As you can see in the definition...

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What is /sci/'s usual response to the problem of induction? Is it something that does not really bother you?
>>
>>8454720
That's the one that the axiom of infinity cannot be proven via first principles right?

The inductive set and naturals model a very large finite set pretty well without worrying about just how big that very large set is.
Sure you could prove that induction works on every finite set via first principles...but I'm lazy and that sounds boring.
ne?
>>
>>8454747

>>
>>8454720

>If you tried to doubt everything you would not get as far as doubting anything. The game of doubting itself presupposes certainty.

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Can someone teach me long division and multiplication?
>>
>>8454717

What other way is there? Like what is it that they actually teach you to do?
Maybe I'm just old... but I'm only 24...
>>
>>8454723
Go to sleep grandpa
>>
>>8454717
I honestly just don't know how to write it out. Fuck the public school system failed me, i basically winged it through high school. I think my algebra 1 teacher thought I was downright retarded or she wanted my dick. She literally just answered my work for me.

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